Brewing climate friendly tea in the garden

Recently, when I was attending my local community seed swop in rural Lewes in East Sussex, in England, I came across an allegedly environmentally friendly version of charcoal called biochar, which the industry mouthpieces are promoting as an alleged way of keeping carbon in the soil reducing greenhouse gas emissions, while at the same time improving soil fertility and thus the productivity of crops. Really?

It is fairly well known that you can use charcoal to heat your house or to cook your food. Biochar, however, is a type of coal that is created when you burn biomass and the biochar industry is promoting biochar as an alleged way of keeping carbon in the soil and thus reducing greenhouse gas emissions from the soil, while at the same time improving soil fertility and thus the productivity of crops. This concept is currently being sold to unsuspecting farming communities around the world, but it could be a complete waste of money as the actual benefit of biochar is yet to be proven.

In Lewes, the biochar industry lobby was a the seed swap, where it was trying to bring on board unsuspecting but keen allotment holders to the biochar cause, by telling them how biochar can be used to make the local soil more fertile, though the degree to which results offer long term carbon sequestration in practice has been challenged.

The industry wants to launch biochar commercially in rural communities around the world; the seed swap in Lewes provides the industry with the right test audience. The seed swap features among other things practical advice on saving seed, good fruit tree health, willow weaving, and this year also biochar stoves for tea-making.

In principle, adding a stable form of organic carbon to farm soils is a good old idea; it could sequester carbon and at the same time increase soil fertility and farm productivity. This is the principle of proven ecological farming practices. Current biochar projects are however mainly small scale and still in development. Despite this, the biochar lobby is already touting this potentially false unproven climate solution, which could prove to waste money that could be better spent on developing more certain ecological practices, like avoiding bare soil, growing legumes and cover crops. So, biochar may not be the right way to go for small farming communities in England or elsewhere in the world. Uncertainties surrounding biochar include how long the carbon would actually be locked in the soil, and how biochar improves soil fertility in the first place as simple chicken manure has been shown to produce higher crop yields than fertilizing with biochar.

The biochar lobby may well be using local community-based events, like the seed swap in Lewes, to build grassroots support for their business, but their optimistic claims need to be balanced with information about the uncertainty of their solution and the corporate interests in getting biochar and soil carbon included into carbon markets.

Testing biochar in my own allotment may tell me something about its use in improving soil fertility and yields, but testing for soil organic carbon is not something that can be done in the back garden and will probably not prove to be any allotment owner’s cup up tea!

In the context of chemical fertilisers, biochar may be seen as a 'false' solution to climate change mitigation in agriculture and an obstacle for a real move towards ecological soil fertility without chemical fertilisers and without green washing.

Iza Kruszewska is a sustainable agriculture campaigner for Greenpeace International. Iza lives and works in Lewes, where she is active in the local allotment community.

Clarification added on 20 February 2012: There were two talks on biochar at Seedy Saturday: one by James Greyson on making biochar cookers; and one by Craig Sams from Carbon Gold on the use of biochar in developing countries. Iza did not go to the talk by James Greyson on biochar cookers and the blog refers to the talk by Craig Sams, not the talk by James Greyson.

Iza makes some interesting points, but the overuse of 'false' and 'alleged' and 'unsuspecting' shows her bias. I was that ...

Iza makes some interesting points, but the overuse of 'false' and 'alleged' and 'unsuspecting' shows her bias. I was that 'industry mouthpiece' and one man 'biochar industry lobby' at the Lewes Seedy Saturday - urged to come and speak there by the Transition Towns people who organised it. As a Greenpeace supporter since the 1970s, a Soil Association trustee for 18 years and a pioneer of organic food I think I deserve better, but that's not my point. Nobody is forcing biochar on anyone. Unlike biofuels or GM crops, there are no subsidies for biochar. Yet farmers who have tried it are increasing their usage. In Belize organic cacao farmers have installed 10 kilns to make their own biochar because it shortens the wait by 3 years for a cacao tree to start fruiting. They wouldn't waste their time making it if they hadn't been to the 5 separate trial locations where trees with biochar flourish alongside those without. Delfland Plants, the main propagator of organic vegetable plugs for commercial organic growers are on record, after trials in 2011, as saying that biochar seed compost is the first peat-free compost that performs as well as their usual peat-based seed compost.
I gave Iza a sample pack of biochar. I hope her allotment trials reflect its benefits, assuming no experimental bias, of course!
Biochar works best with organic farming, so it fits with cover crops, green manures and growing legumes. It has Soil Association certification as an approved input. Some commercial growers have already switched over 100% to GroChar (our microbiologically enhanced form of biochar) because they want to stop using peat and have finally found an alternative.
In Australia this July there will be a carbon tax - farmers who use biochar will get credits for putting it in the ground, more credits to reflect the 2 tonnes per hectare increase in soil microbe population it generates and ongoing credits for the halving of nitrous oxide emissions yearly thereafter. Call it greed if you like, but it's high time that carbon was priced on a scientific basis instead of being used as a figleaf for biofuel subsidies and payments for Roundup Ready 'no till' farming.
If you're reading this and want to see what this particular 'industry mouthpiece' has to say about biochar, check out our website at www.carbongold.com. Biochar is a story that is up and coming and everyone who cares about climate change and soil degradation should seek to make an informed judgement.
Craig Sams

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(Unregistered) Anony
says:

The intellectual, financial, chemical and physical positives of biochar, as seen through the effects of Terra Preta soils of Amazonia, are incredible....

The intellectual, financial, chemical and physical positives of biochar, as seen through the effects of Terra Preta soils of Amazonia, are incredible. There is, however, an elephant in the room when you discuss biochar. This is bulk density. The bulk density of biochar - it is really just charcoal - is much less than that of the soil which you might want to ameliorate. So when you try to add it/mix it (with the corresponding SOC loss) into soil it stays there until the first good drenching rain. Whereupon it floats to the top of the soil and runs-off.

There are industry interests involved in funding the research into biochar (sponsored PhDs) - as I found when I was doing research in Australia - and they never like to discuss the practicalities of their soil ameliorate as it floats off downstream.

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(Unregistered) CharlesB
says:

For those who are interested in learning what the scientific community actually is learning about biochar, I recommend the Australian Government Depar...

For those who are interested in learning what the scientific community actually is learning about biochar, I recommend the Australian Government Department of Agriculture's publication "Biochar: implications for agricultural productivity."

Unlike the author of this article who only offers unsubstantiated opinions and invectives, this report does a good job of reviewing current scientific research and provides a balanced view of the potential and challenges of biochar use.

I personally have read over 200 peer reviewed studies related to biochar and have come to the conclusion that this is a promising pathway to heal depleted soils while beginning to reverse the effects of excess CO2 in our atmosphere. It is not a magic bullet, but it is a sensible addition to organic farming and nutrient cycle management.

Ray' O'Grady's ( http://www.smartbugs.com.au/ ) very interesting work with PandA (liquid Wood smoke) for anthrocnose & phytopthora root rot. Given the current controls, this sounds like a cost & environmental godsend.

Also in OZ, they are showing that composting with Char & liquid wood smoke result in a 74% savings of NH3 that in normal composting is lost to the air.

I urge you all to support the philanthropic clean cook stove efforts of Dr. "TLUD" Paul Anderson. A leader among a group of engineers without borders spreading the cascade of health benefits from the gasification of biomass.
Biomass Energy Foundation (BEF) website http://biomassenergyfndn.org/bef/

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(Unregistered) Caroline
says:

Thank you Craig and everyone else for your comments.

It is easy to mix up soil fertility and soil carbon sequestration. Biochar may well ...

Thank you Craig and everyone else for your comments.

It is easy to mix up soil fertility and soil carbon sequestration. Biochar may well improve productivity by increasing soil fertility in some soils; but its ability to store carbon in soils in the long-term and mitigate greenhouse gas emissions has still to be proved. Giving credits for something yet to be proven is effectively slowing down real solutions such as many ecological farming practices.

On the uncertainty surrounding soil organic carbon persistence in soils in general, and biochar in particular, we suggest the following peer-review articles, plus the ones reviewed in the recent report by Misereor (http://m.misereor.de/fileadmin/redaktion/Report1_Biochar_111122.pdf):

Perses Bilimoria, The Society of Biochar Initiatives, India ... New Zealand; Thomas Harttung, BlackCarbon A/S and GreenCarbon A/S, Denmark ... the biogeochemistry of black carbon and the development of biochar and bioenergy systems. ...

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(Unregistered) Mike
says:

" but testing for soil organic carbon is not something that can be done in the back garden "

Iza makes this testing sound like rocket science, there are many easy tests to determine the effects of biochar. Some are quite simple, the worm avoidance test takes a box 12x24x2 inches approximatly, enough top soil to fill it 75% and enough biochar for the other 25%. Add charged biochar to the soil in 1/2 of the box leave the remainder unconditioned. Put 10 worms on the line between the 2 halves keep moist and let them do their thing.

Wait 2 - 7 days flip the box over and see where the worms are. If they prefer the biochar side that is a good indication it is a beneficial additive.

There are many simple tests like this that can guide the home gardener as to the benefits of biochar. They can be found at the IBI web site http://www.biochar-international.org/

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(Unregistered) Bazman
says:

Hello Iza

Biochar is all about improving soil structure. it is not and I repeat it is not a fertiliser. Well made Biochar has a high cati...

Hello Iza

Biochar is all about improving soil structure. it is not and I repeat it is not a fertiliser. Well made Biochar has a high cation exchange capacity, great moisture holding ability among many other positive qualities. When used with fertilisers, be they organic or not, quality Biochar will hold those nutrients and exchange those with plants or soil fungi. Biochar properly inoculated will improve soil structure and increase soil biota. Biochar will work best in poor and limited soils and this is where you will see the best results. Research into Biochar and Trichoderma will revolutionise the organic food production industry in the next few years.

Biochar is classed as a product developed for the agri/horticultural industries using controlled heat and limited oxygen, processes which reduce carbon loss and ash yields with controlled and/or scrubbed emissions. Many of these systems have been developed to produce excess energy in the form of Bio-oils, syn-gas and heat energy. Charcoal in general is made in pits and used to fuel BBQs and other areas outside of soil improvement. It is also often hydrophobic with high ash content making it unsuitable for soil application.

If you are going to use Biochar make sure you inoculate it with compost and/or soak it in liquid nutrients before application, this removes issues of possible nitrogen draw down effects. Biochar 0.2 to a maximum of 5mm should be speckled through your top soil profile, if it is washing away your Biochar is in the wrong part of your soil profile. Quality Biochar should come with 25-35% moisture content and is hydrophilic and should not float.

Biochar is a strong partner of those who want to improve soils organically with compost, green manures, rock minerals, fungi, nutrient teas, mulching, no-dig, no-till, permaculture and biodynamics. Biochar is part of a great range of powerful tools for those of us who have green thumbs and love our productive soils.

I am a permaculture designer, organic gardener, small Biochar business owner and I have been making and using Biochar for over 7 years in my food forest system. Biochar like most things needs to be applied with knowledge and care.